Answer to Question #291 Submitted to "Ask the Experts"

Q

I'm doing a lab that deals with radioactive materials. We are measuring count, such as ⁹⁰Sr. How do I know that these samples won't cause any harm to me? These samples are from a company that sells these labs.

A

It sounds like you work in a laboratory processing human samples that could contain any radionuclide including the ⁹⁰Sr in your question. In most cases, where the sample is a few milliliters of blood or less than a gram of tissue, the amount of radioactivity is pretty small and to be measured it must be counted in a special instrument (e.g., gamma or liquid scintillation counter). Since humans have about 4000-5000 milliliters of blood in our bodies, what we collect in one milliliter would be 1/4000th or 1/5000th of what is present in the bloodstream. There are some cases where the sample might contain a higher amount of radioactivity. An example would be blood drawn immediately after an individual received ¹³¹I for radiation therapy. Lead shielding might be recommended for the sample containers because the activities administered to patients for therapy are significantly higher than what is administered for routine diagnostic tests and the amount of blood in each sample could be 10 ml or more. The potential for hazard from any of these samples is greatest if you have an accidental intake of the material (eat it, breathe it, absorb it through a cut on the skin). The best protection is universal precautions. Wear gloves–double glove. Wear eye protection (or full face protection) if there is a chance of splashing. Wear a lab coat or disposable gown to cover your own clothing. Watch your technique–hand-to-face contact happens frequently without even thinking about it, providing an easy path for something on your hands to get in your mouth. These precautions should be taken with human blood or body fluids anyway and they minimize the potential for you to ingest or absorb radioactive material. There is little or no hazard to you as long as you follow basic universal precautions.